Strategically located, traders, invaders, and nomadic tribes have also used it as a gateway to and from the South Asia.
The British took the threat of a Russian invasion of South Asia via the Khyber and Bolan Passes very seriously so in 1837, a British envoy was sent to Kabul to gain support of the Emir, Dost Mohammed. In February 1839, the British Army under Sir John Keane took 12,000 men through the Bolan Pass and entered Kandahar, which the Afghan Princes had abandoned; from there they would go on to attack and overthrow Ghazni.
In 1879 at the close of the Second Afghan War, the Treaty of Gandamak, the Bolan Pass was brought under British control; this was when the Sind-Pishin Railway was built by the British across the pass between Kandahar and Quetta.
The Bolan Pass is an important pass on the Baluch frontier, connecting Jacobabad and Sibi with Quetta, which has always occupied an important place in the history of British campaigns in Afghanistan. Since the treaty of Gandamak, which was signed at the close of the first phase of the Afghan War in 1879, the Bolan route has been brought directly under British control, and it was selected for the first alignment of the Sind-Pishin railway from the plains to the plateau. From Sibi the line runs south-west, skirting the hills to Rindli, and originally followed the course of the Bolan stream to its head on the plateau. The destructive action of floods, however, led to the abandonment of this alignment, and the railway now follows the Mashkaf valley (which debouches into the plains close to Sibi), and is carried from near the head of the Mashkaf to a junction with the Bolan at Mach. An alternative route from Sibi to Quetta was found in the Harnai valley to the N.E. of Sibi, the line starting in exactly the opposite direction to that of the Bolan and entering the hills at Nari. The Harnai route, although longer, is the one adopted for all ordinary traffic, the Bolan loop being reserved for emergencies. At the Khundilani gorge of the Bolan route conglomerate cliffs enclose the valley rising to a height of 800 ft., and at Sir-i-Bolan the passage between the limestone rocks hardly admits of three persons riding abreast. The temperature of the pass in summer is very high, whereas in winter, near its head, the cold is extreme, and the ice-cold wind rushing down the narrow outlet becomes destructive to life. Since 1877, when the Quetta agency was founded, the freedom of the pass from plundering bands of Baluch marauders (chiefly Marris) had been secured by the British Indian Army.